From mboxrd@z Thu Jan 1 00:00:00 1970 From: michal.simek@xilinx.com (Michal Simek) Date: Fri, 31 Jan 2014 13:08:05 +0100 Subject: [PATCH] ARM: zynq: Reserve not DMAable space in front of the kernel Message-ID: <780bb8c8fd752eeace2fd2fbe1d8ed8572dc0d76.1391170073.git.michal.simek@xilinx.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Reserve space from 0x0 - __pa(swapper_pg_dir), if kernel is loaded from 0, which is not DMAable. It is causing problem with MMC driver and others which want to add dma buffers to this space. Signed-off-by: Michal Simek --- Jason: I don't think it is worth to bring 0x8000 magic value and count minimum from it and phys_addr of swapper_pg_dir. Full 512k of memory shouldn't be used by DMA. --- arch/arm/mach-zynq/common.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/arch/arm/mach-zynq/common.c b/arch/arm/mach-zynq/common.c index 1db2a5ca..8c09a83 100644 --- a/arch/arm/mach-zynq/common.c +++ b/arch/arm/mach-zynq/common.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include @@ -41,6 +42,18 @@ void __iomem *zynq_scu_base; +/** + * zynq_memory_init - Initialize special memory + * + * We need to stop things allocating the low memory as DMA can't work in + * the 1st 512K of memory. + */ +static void __init zynq_memory_init(void) +{ + if (!__pa(PAGE_OFFSET)) + memblock_reserve(__pa(PAGE_OFFSET), __pa(swapper_pg_dir)); +} + static struct platform_device zynq_cpuidle_device = { .name = "cpuidle-zynq", }; @@ -117,5 +130,6 @@ DT_MACHINE_START(XILINX_EP107, "Xilinx Zynq Platform") .init_machine = zynq_init_machine, .init_time = zynq_timer_init, .dt_compat = zynq_dt_match, + .reserve = zynq_memory_init, .restart = zynq_system_reset, MACHINE_END -- 1.8.2.3 -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 198 bytes Desc: not available URL: